Bovine ephemeral fever epidemics in Kingdom Saudi Arabia: clinical, epidemiological and molecular investigation.

INTRODUCTION: Bovine ephemeral fever virus (BEFV) is an arthropod borne Rhabdovirus affects cattle and water buffalo causes acute febrile disease. METHODOLOGY: The clinical picture and epidemiological pattern of BEF were described among cattle in epidemics of 2007, 2009 and 2011 in four geographical regions of Kingdom Saudi Arabia (Eastern, Jizan, Qasim, and Riyadh). Serum samples were tested using VNT. Virus isolation and molecular characterization were carried out for the first time in KSA. RESULTS: The main clinical symptoms were fever, stiffness, lameness, salivation and subcutaneous emphysema. The prevalence and the mortality rate of BEF have decreased from 70% and 4.6% in 2007 to 30% and 0.6% in 2011, respectively in the 4 studied areas. There was no region association with higher prevalence of BEF. The intracluster correlation (ICC) was estimated for the first time in KSA as 0.0034. BEFV had been isolated from 11 out of 20 samples (55%) and isolation was confirmed by VNT. The molecular detection of BEFV by RT-PCR and real- time RT-qPCR were found more sensitive for diagnosis of the disease than virus isolation; 80% and 90% for the former tests and 55% for the latter. Three isolates were sequenced, they showed 84.7% - 100% identities in between and shared 90.4%-96.5% sequence identity with a previously published sequence from Australia (KF679404). The generated sequences belonged to 3rd cluster of BEFV glycoprotein. CONCLUSIONS: BEF occurrence has cyclic nature and the efficacy of vaccines prepared from local strains has to be evaluated and considered in diseases control.

Risk analysis and seroprevalence of bovine ephemeral fever virus in cattle in the Kingdom of Saudi Arabia.

Bovine ephemeral fever virus (BEFV) is an arthropod-borne rhabdovirus that causes disabling clinical signs and major economic losses in cattle and water buffalo. The disease is well documented in Asia, Africa, and the Middle East; however, the seroprevalence of BEFV in different regions and bovine breeds in the Kingdom of Saudi Arabia (KSA) is unknown. The aim of this study was to analyze risk factors which affect the prevalence of antibodies against BEFV in small herds of cattle in four geographical regions of KSA. A total of 1480 serum samples from non-BEFV vaccinated small herds of cattle were collected from the Eastern, Jizan, Qasim, and Riyadh regions (370 samples per region) during the summer of 2010. Serum neutralization test was used to detect antibodies against BEFV. There was a significant effect of region, breed, sex, and age on the seroprevalence of BEFV. Seropositive ratios were 18, 18, 26, and 12 % for the Eastern, Jizan, Qasim, and Riyadh regions, respectively (P = 0.00002); 23.2 % for dairy and 13.7 % for non-dairy breeds (P = 0.00004); 24.4 % for males and 14.6 % for females (P = 0.00004); and 15.4, 29.1, and 11.4 % for animals <1 year, 1-3 years, and >3 years, respectively (P < 0.001). Risk analysis showed a significant effect of different regions of KSA on the seroprevalence of BEFV. Host risk factors (age, sex, and breed) showed also a significant effect on the seroprevalence of BEFV. This indicates active circulation of this virus in small herds of cattle. Insect control strategies and BEFV vaccination programs during the spring are recommended to reduce the spread of BEFV and minimize subsequent economic losses as this is adopted in many enzootic countries.

Lack of middle East respiratory syndrome coronavirus transmission from infected camels.

To determine risk for Middle East respiratory syndrome coronavirus transmission from camels to humans, we tested serum from 191 persons with various levels of exposure to an infected dromedary herd. We found no serologic evidence of human infection, suggesting that zoonotic transmission of this virus from dromedaries is rare.

Genome-wide analysis of the emerging infection with Mycobacterium avium subspecies paratuberculosis in the Arabian camels (Camelus dromedarius).

Mycobacterium avium subspecies paratuberculosis (M. ap) is the causative agent of paratuberculosis or Johne's disease (JD) in herbivores with potential involvement in cases of Crohn's disease in humans. JD is spread worldwide and is economically important for both beef and dairy industries. Generally, pathogenic ovine strains (M. ap-S) are mainly found in sheep while bovine strains (M. ap-C) infect other ruminants (e.g. cattle, goat, deer), as well as sheep. In an effort to characterize this emerging infection in dromedary/Arabian camels, we successfully cultured M. ap from several samples collected from infected camels suffering from chronic, intermittent diarrhea suggestive of JD. Gene-based typing of isolates indicated that all isolates belong to sheep lineage of strains of M. ap (M. ap-S), suggesting a putative transmission from infected sheep herds. Screening sheep and goat herds associated with camels identified the circulation of this type in sheep but not goats. The current genome-wide analysis recognizes these camel isolates as a sub-lineage of the sheep strain with a significant number of single nucleotide polymorphisms (SNPs) between sheep and camel isolates (∼1000 SNPs). Such polymorphism could represent geographical differences among isolates or host adaptation of M. ap during camel infection. To our knowledge, this is the first attempt to examine the genomic basis of this emerging infection in camels with implications on the evolution of this important pathogen. The sequenced genomes of M. ap isolates from camels will further assist our efforts to understand JD pathogenesis and the dynamic of disease transmission across animal species.